5 Clues That It’s Time to Change Your Pool Filter Cartridge

dirty2So my sister sent me this picture of her pool filters that she changed out recently. Besides making me go, “Ewwww!” it made me ponder how one knows just when it’s time to change out the cartridges versus just clean them. As with any type of filter there is no hard and fast rule that says your filter will last X amount of time. It depends on the application, the quality of water passing through, quality of cartridge, usage rate, etc. There are definite indicators, though, that it’s time to change out the cartridges for new ones.

  1. Broken bands – If your filter cartridges have bands and several of them are broken, it is time to change the filter. Bands play an important role in keeping the pleats from flattening out when under pressure, allowing for the optimal surface area. As an aside, I’ve talked to some contractors who say they cut the bands to make cleaning easier. DON’T DO THIS!
  2. Fabric is frayed – Cartridges are generally made of polyester media which, over time, will wear out from repeated torture from suspended particles and chemicals that the pump is forcing through it. The material will start to look ‘hairy’ or even develop visible holes, allowing debris to pass through and back into your pool. In the words of comedian Bill Engvall, ‘There’s your sign!”
  3. Pleats are flattening – Over time the integrity, or rigidity, of the material diminishes and the pleats begin to flatten. For the same reasons as mentioned above, this is not ideal.
  4. Cracked endcaps – Over time the endcaps of a filter can become brittle and weaker from constant pressure and chemical exposure. Due to advances in manufacturing, the media will most often wear out far before the endcaps crack.
  5. Flow doesn’t change – In our video How to Change Your Filter Cartridge, we discuss the differential pressure gauge and how to determine when your filter needs cleaning. When the pressure gauge reads 10-12 psi above that recorded when new filters are installed it’s time to clean your filter cartridges. When the pressure reading remains the same or only slightly decreases after cleaning them, it’s likely time to replace the cartridges as the dirt and oils have embedded themselves within the fabric of the cartridge. At this stage the cartridges wclean2ill no longer appear clean either, even after cleaning.

Cartridge selection is important in extending the time between filter change-outs. FILBUR Manufacturing uses only REEMAY Filtration Fabric made from high-quality, continuous-filament, nonwoven polyester in the production of its filter cartridges. “This helps create extremely durable filter cartridges that hold up to the rigors of cleaning.  However, by their nature of ‘trapping’ contaminant particles, eventually complete cleaning of the filaments is not possible. Since uniformity is key to keeping water sparkling clear, it is important to replace cartridges regularly, ” says John Neely, Global Marketing Manager for Fiberweb.

Filter media type and weight does make a difference. 4 ounce media is recommended for pool applications, lasting anywhere from 3-5 years, while 3 ounce media is more suited to spa applications. Three ounce media in a pool application will have a much shorter life than its 4-ounce counterpart.

As any pool owner knows, filter cartridges, not to mention the rest of the pool package, is quite an investment, but with regular maintenance that investment can pay back many times over in time spent with family and friends enjoying summer around the pool. Happy (and clean) swimming!



About Shelly

Shelly Johnson is the Marketing Manager for FILBUR Manufacturing – producer of pool and spa cartridges and D.E. grids and top supplier to spa manufacturers. Shelly has been in the water filtration business for over 20 years and has been a contributor to AQUA Magazine.

  • davidnorwood

    I have never changed my filters in my in-ground 1600 gal spa, which was built in 2000—I believe Hayward filters. We use the spa sporadically– maybe only as little as a month a year. but run the pump to heat the water and after it rains or if the spa gets dirty.

    I clean the filters around 1 times a year using a pressure washer, which normally has gray/brown staminate, which washes off with ease. When I am done the filters look good –mostly white with some minor brown color or staining on some edges of the filter.
    The water is city water, which some consider hard, but I do not see much or any calcium build-up on the filters, but I could be wrong. The water hardness is 250 ppm out of the hose, but when I tested recently, it was 500 ppm- so I recently drained the spa and it is currently empty while I do repairs.

    None of the “5 clues” above seem to pertain, so except for the staining the filters look used but like new and you pointed out there is no hard-fast-rule.
    So, should I change my filters for my application after 13 years? Or, because they are not showing much ware, can I continue using the filters?

    • http://filburmfg.com/ Shelly Johnson

      Hi, David –
      I apologize for the delay in my response. Thank you for your question.

      I would highly recommend changing your filter cartridges at least every 2 years. You were correct in that hardness build-up is not always evident. This build-up can occur within the fibers of the media and will become embedded over time, not necessarily causing discoloration. This will lead to flow restriction and may cause undue stress on your spa over time. Most cartridge media that is used today is highly resistant to chemicals but over time any media will start to degrade which may lead to some bypass as well.

  • Victoria Downing

    Help, we are using FC-0303 filters for our spa. Do we need to remove the sticky paperlike band? My husband told me to but I cannot get them off which makes me think I was supposed to leave them alone. ??

    • http://filburmfg.com/ Shelly Johnson

      Hello, Victoria – Your hunch is correct. The bands should be kept intact to maintain the spacing between the pleated material and prevent flattening of the pleats. This will allow the maximum surface area for filtration and the longest life for your cartridge. Thanks for the question!

  • http://www.poolfilters.biz/ Jeny Thomas

    Quite impressive post it is. It is necessary to check the catridges at regular intervals like flow of water passing, quality,usage etc.The indicators and the points which you have mentioned is quite helpful. I have also got many ideas and points through your blog. Thanks for sharing such a nice blog.